Estimating the epicentral distance from a single station is a critical task in real-time earthquake early warning systems. To address the limitations of the traditional B-Δ method, which relies on limited P-wave information and exhibits significant prediction errors, this study utilizes strong-motion data from the Japan K-NET network. A 3-second time window of three-component acceleration waveforms is used as input to a convolutional neural network (CNN), which directly extracts feature information from the waveforms to establish a CNN-based epicentral distance estimation model (CNN-Dis). The results show that in the test dataset, by normalizing both the input data and labels, the CNN-Dis model achieves an mean absolute error (MAE) of 28.119 6 km and a standard deviation of 34.682 7 km, outperforming the model without normalization. Compared to the traditional B-Δ method, the CNN-Dis model improves the reliability of epicentral distance estimation. Moreover, the CNN-Dis model provides relatively reliable results for offshore earthquakes, in contrast to inland events. The CNN-Dis model enhances the accuracy of epicentral distance estimation to a certain extent and provides strong support for the iteration and performance optimization of earthquake early warning technologies.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |